The present invention is an improved insulation for use in the walls and ceilings of various enclosures, especially buildings. The heat loss by conduction through the walls and ceilings in home dwellings typically amounts to over 50 percent of the total heat required with the balance being lost through windows, doors, the floor, and air drafts. This loss through the walls is primarily limited by the space that is available for insulation and by the thermal conductivity of the insulating material.
Fluorocarbon gas filled fibrous insulations have been used to some advantage to insulate refrigerator walls. However, they have not been used to insulate buildings because the prior art does not include a low cost, low thermal conductivity, ultra low diffusion, fire resistant, durable casing for such insulation.
U.S. Pat. No. 1,969,621 discloses metal casings to provide the gas tight seal but with the disadvantage of high conductivity losses. U.S. Pat. Nos. 2,779,066; 2,939,811; and 3,004,877 disclose ultra low permeability thick polymeric and copolymeric films such as saran or polyvinylidene chloride and polyvinyl alcohol which have been used with moderate success for relatively short periods of time, perhaps a decade, but the cost of thick polymeric films is high for building insulation and the gas diffusion rate is too great for long-term applications, U.S. Pat. No. 3,264,165 shows that laminations of various types of polymers, paper, and metal films have been used with adequate success but at a prohibitive cost.